1. Field of the Invention
The present invention relates to a driving method of a plasma display panel (PDP) and to the circuitry developed for generating and applying appropriate driving voltages.
2. Discussion of the Related Art
A plasma display device is a flat panel display that uses plasma generated by a gas discharge process to display characters or images. It includes a PDP with tens to millions of pixels provided in a matrix format, depending on the size of the PDP. A PDP may be classified as a DC PDP or an AC PDP, according to its discharge cell structure and the waveform of the driving voltage applied.
The DC PDP has electrodes exposed in a discharge space, allowing a current to flow in the discharge space while a voltage is supplied. The DC PDP, therefore, requires a resistor for limiting the current. On the other hand, the AC PDP electrodes are covered with a dielectric layer that forms a capacitor to limit the current and protects the electrodes from the impact of ions during discharge. Accordingly, the AC PDP has a longer lifespan than the DC PDP.
One frame of the PDP is defined as a period of time during which all of the pixels in the panel are addressed. One frame is divided into a plurality of subfields, and each subfield includes a reset period, an address period, and a sustain period. The reset period is for initializing the status of each discharge cell so as to facilitate an addressing operation on the discharge cell. The address period is for selecting turn-on/turn-off cells, that are the cells that must be turned on or turned off, and for accumulating wall charges on the turn-on cells that are addressed to be turned on. The sustain period is for causing the cells to either continue discharge for displaying an image on the addressed cells or remain inactive.
In order to perform the above operations and to display an image, sustain pulses are alternately applied to scan electrodes and sustain electrodes during the sustain period, and reset waveforms and scan waveforms are applied to the scan electrodes during the reset period and the address period. Therefore, a scan driving board for driving the scan electrodes and a sustain driving board for driving the sustain electrodes are separately needed. Mounting the two separate driving boards on a chassis base may generate problems and increase the overall cost of the device.
For combining the two driving boards into a single combined board, schemes of coupling the single combined board to the scan electrodes and extending the sustain electrodes to reach the combined board have been proposed. However, when the two driving boards are combined as such, the impedance component created at the extended sustain electrodes is increased.